Assessment of non-invasive time and frequency atrial fibrillation organization markers with unipolar atrial electrograms.


:The standard electrocardiogram (ECG) is the most common non-invasive way to study atrial fibrillation (AF). In this respect, previous works have shown that the surface lead V(1) reflects mainly the dominant atrial frequency (DAF) of the right atrium (RA), which has been widely used to study AF. In a similar way, AF organization and fibrillatory (f) wave amplitude are two recently proposed non-invasive AF markers. These markers need to be validated with invasive recordings in order to assess their capability to reliably reflect the internal fibrillatory activity dynamics. In this work, these two non-invasive metrics have been compared with similar measures recorded from two unipolar atrial electrograms (AEGs). For both ECG and AEG signals, AF organization has been computed by applying a nonlinear regularity index, such as sample entropy (SampEn), to the atrial activity (AA) and to its fundamental waveform, defined as the main atrial wave (MAW). The surface and epicardial f wave amplitude has been estimated through their mean power. Results obtained for 38 patients showed statistically significant correlations between the values measured from surface and invasive recordings, thus corroborating the usefulness of the aforesaid markers in the non-invasive study of AF. Precisely, for AF organization computed from the MAW, the correlation coefficients between surface and both AEGs were R = 0.926 (p < 0.001) and R = 0.932 (p < 0.001). For f wave amplitude, slightly lower significant relationships were noticed, the correlation coefficients being R = 0.765 (p < 0.001) and R = 0.842 (p < 0.001). These outcomes together with interesting linear relationships found among the parameters suggest that AF regularity estimated via SampEn and f wave amplitude can non-invasively characterize the epicardial activity related to AF.


Physiol Meas


Alcaraz R,Hornero F,Rieta JJ




Has Abstract


2011-01-01 00:00:00














  • In vitro measurements of respiratory mechanics during HFPV using a mechanical lung model.

    abstract::High-frequency percussive ventilation (HFPV) may be defined as flow-regulated time-cycled ventilation that creates controlled pressure and delivers a series of high-frequency subtidal volumes in combination with low-frequency breathing cycles. In recent years, the usefulness of HFPV has been clinically assessed as an ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Riscica F,Lucangelo U,Ferluga M,Accardo A

    更新日期:2011-06-01 00:00:00

  • Electroencephalogram classification in motor-imagery brain-computer interface applications based on double-constraint nonnegative matrix factorization.

    abstract:OBJECTIVE:Brain-computer interfaces (BCIs) are aimed at providing a new way of communication between the human brain and external devices. One of the major tasks associated with the BCI system is to improve classification performance of the motor imagery (MI) signal. Electroencephalogram (EEG) signals are widely used f...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Su J,Yang Z,Yan W,Sun W

    更新日期:2020-08-11 00:00:00

  • A wireless platform for in vivo measurement of resistance properties of the gastrointestinal tract.

    abstract::Active locomotion of wireless capsule endoscopes has the potential to improve the diagnostic yield of this painless technique for the diagnosis of gastrointestinal tract disease. In order to design effective locomotion mechanisms, a quantitative measure of the propelling force required to effectively move a capsule in...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Natali CD,Beccani M,Obstein KL,Valdastri P

    更新日期:2014-07-01 00:00:00

  • A deep neural network for estimating the bladder boundary using electrical impedance tomography.

    abstract:OBJECTIVE:Accurate bladder size estimation is an important clinical parameter that assists physicians, enabling them to provide better treatment for patients who are suffering from urinary incontinence. Electrical impedance tomography (EIT) is a non-invasive medical imaging method that estimates organ boundaries assumi...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Konki SK,Khambampati AK,Sharma SK,Kim KY

    更新日期:2020-12-18 00:00:00

  • Differences in the microcirculatory effects of local skin surface contact pressure stimulation between acupoints and nonacupoints: possible relevance to acupressure.

    abstract::In the present study, laser Doppler measurement was used to quantitatively investigate the microcirculatory effects of contact pressure stimulation (PS) underneath the Hoku acupoint and its nearby nonacupoint, to improve the understanding of the mechanisms underlying acupressure therapy. A control group (no PS applied...

    journal_title:Physiological measurement

    pub_type: 临床试验,杂志文章


    authors: Hsiu H,Hsu WC,Chen BH,Hsu CL

    更新日期:2010-06-01 00:00:00

  • Validation of a new dielectric device to assess changes of tissue water in skin and subcutaneous fat.

    abstract::Easily applicable and inexpensive water-specific techniques to evaluate local oedema, swollen tissue problems and fluid retention in humans are not available. In the present investigation a recently constructed non-invasive device for a local measurement of changes in tissue water in human skin and subcutaneous fat (S...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Nuutinen J,Ikäheimo R,Lahtinen T

    更新日期:2004-04-01 00:00:00

  • Snore site discrimination using statistical moments of free field snoring sounds recorded during sleep nasendoscopy.

    abstract::The non-invasive measurement of free field snoring sounds to estimate the site of snoring is an important development in the diagnosis, treatment and management of sleep-related breathing disorders. We investigated characteristics of the probability density function by testing the sensitivity of the statistical moment...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Beeton RJ,Wells I,Ebden P,Whittet HB,Clarke J

    更新日期:2007-10-01 00:00:00

  • Coordinated FA-MS and SIFT-MS analyses of breath following ingestion of D2O and ethanol: total body water, dispersal kinetics and ethanol metabolism.

    abstract::A coordinated study of the dispersal of water between the various body compartments (stomach and gut, blood stream and tissue) and the similar dispersal kinetics of ethanol and its metabolism has been carried out involving two healthy volunteers using flowing afterglow mass spectrometry, FA-MS, and selected ion flow t...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Spanel P,Wang T,Smith D

    更新日期:2005-08-01 00:00:00

  • Influence of tidal volume and positive end-expiratory pressure on ventilation distribution and oxygenation during one-lung ventilation.

    abstract:OBJECTIVE:The aim of the study was to explore the feasibility of titrating tidal volume (V T) and positive end-expiratory pressure (PEEP) during one-lung ventilation (OLV) based on ventilation distribution and oxygenation. APPROACH:Twenty-four consecutive patients requiring intubation with a double-lumen tube and subs...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Zhao Z,Wang W,Zhang Z,Xu M,Frerichs I,Wu J,Moeller K

    更新日期:2018-03-29 00:00:00

  • Infrared thermography for indirect assessment of activation of brown adipose tissue in lean and obese male subjects.

    abstract::Brown adipose tissue (BAT) plays a key role in adaptive thermogenesis in mammals, and it has recently been considered as an attractive therapeutic target for tackling human obesity by increasing energy expenditure. Thermal imaging using infrared thermography (IRT) has emerged as a potential safe, rapid and inexpensive...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: El Hadi H,Frascati A,Granzotto M,Silvestrin V,Ferlini E,Vettor R,Rossato M

    更新日期:2016-12-01 00:00:00

  • The feasibility of in vivo quantification of bone-fluorine in humans by delayed neutron activation analysis: a pilot study.

    abstract::Fluorine (F) plays an important role in dental health and bone formation. Many studies have shown that excess fluoride (F(-)) can result in dental or skeletal fluorosis, while other studies have indicated that a proper dosage of fluoride may have a protective effect on bone fracture incidence. Fluorine is stored almos...

    journal_title:Physiological measurement

    pub_type: 临床试验,杂志文章


    authors: Chamberlain M,Gräfe JL,Byun SH,Chettle DR,Egden LM,Orchard GM,Webber CE,McNeill FE

    更新日期:2012-02-01 00:00:00

  • A finite element model of needle electrode spatial sensitivity.

    abstract::We used the finite element (FE) method to estimate the spatial sensitivity of a needle electrode for bioimpedance measurements. This current conducting needle with an insulated shaft was inserted in a saline solution and the current was measured at the neutral electrode. Model resistance and reactance were calculated ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Høyum P,Kalvøy H,Martinsen ØG,Grimnes S

    更新日期:2010-10-01 00:00:00

  • Multiple breath washout analysis in infants: quality assessment and recommendations for improvement.

    abstract::Infant multiple breath washout (MBW) testing serves as a primary outcome in clinical studies. However, it is still unknown whether current software algorithms allow between-centre comparisons. In this study of healthy infants, we quantified MBW measurement errors and tried to improve data quality by simply changing so...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Anagnostopoulou P,Egger B,Lurà M,Usemann J,Schmidt A,Gorlanova O,Korten I,Roos M,Frey U,Latzin P

    更新日期:2016-03-01 00:00:00

  • Impedance analyser module for EIT and spectroscopy using undersampling.

    abstract::In this paper we present the concept, the design and the test procedure for a DSP-based high-precision and high-performance wide-band (up to 10 MHz) bioimpedance analyser module for application in EIT or bioimpedance spectroscopy. The module implements a digital concept with appropriate signal conditioning hardware fo...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Dudykevych T,Gersing E,Thiel F,Hellige G

    更新日期:2001-02-01 00:00:00

  • Is dynamic cerebral autoregulation measurement using transcranial Doppler ultrasound reproducible in the presence of high concentration oxygen and carbon dioxide?

    abstract::Reliability of cerebral blood flow velocity (CBFV) and dynamic cerebral autoregulation estimates (expressed as autoregulation index: ARI) using spontaneous fluctuations in blood pressure (BP) has been demonstrated. However, reliability during co-administration of O2 and CO2 is unknown. Bilateral CBFV (using transcrani...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Minhas JS,Syed NF,Haunton VJ,Panerai RB,Robinson TG,Mistri AK

    更新日期:2016-05-01 00:00:00

  • Home monitoring of within-breath respiratory mechanics by a simple and automatic forced oscillation technique device.

    abstract::Spirometry is the gold standard to determine the presence of airflow obstruction, but it requires volitional participation and needs qualified supervision. The forced oscillation technique (FOT) measures respiratory input impedance (Zrs) during spontaneous breathing and it could be useful for unsupervised monitoring o...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Dellacà RL,Gobbi A,Pastena M,Pedotti A,Celli B

    更新日期:2010-04-01 00:00:00

  • An abdominal wall simulator for testing suprapubic urinary catheters.

    abstract::Urinary catheters (drainage tubes) are in widespread use. The most common type of long-term catheter is the Foley, which is made from natural or synthetic rubber. Foley catheters are passed into the bladder via the urethra or the suprapubic puncture channel (through the abdominal wall). A simulator for the abdominal w...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Coveney VA,Gröver D

    更新日期:2001-08-01 00:00:00

  • A shape-based quality evaluation and reconstruction method for electrical impedance tomography.

    abstract::Linear methods of reconstruction play an important role in medical electrical impedance tomography (EIT) and there is a wide variety of algorithms based on several assumptions. With the Graz consensus reconstruction algorithm for EIT (GREIT), a novel linear reconstruction algorithm as well as a standardized framework ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Antink CH,Pikkemaat R,Malmivuo J,Leonhardt S

    更新日期:2015-06-01 00:00:00

  • A bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats.

    abstract::This paper presents the design, construction and testing of a device to measure pressure-volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. Ther...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Raghavan K,Feldman MD,Porterfield JE,Larson ER,Jenkins JT,Escobedo D,Pearce JA,Valvano JW

    更新日期:2011-06-01 00:00:00

  • Pulmonary perfusion measured by means of electrical impedance tomography.

    abstract::Electrical impedance tomography (EIT) is a recent imaging technique based on electrical impedance, offering the possibility of measuring pulmonary perfusion. In the present study the influence of several pulmonary haemodynamical parameters on the EIT signal were investigated. First, the influence on the systolic wave ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Vonk Noordegraaf A,Kunst PW,Janse A,Marcus JT,Postmus PE,Faes TJ,de Vries PM

    更新日期:1998-05-01 00:00:00

  • Adverse effects of near current-electrode placement in non-invasive bio-impedance measurements.

    abstract::A major problem confronting application of impedance techniques to studies of disease is the extraction of intrinsic properties of the tissue from the measured impedances, which unavoidably involve geometric factors as well. Amongst the foremost are the sizes and locations of the measuring electrode arrays, and this p...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Shiffman CA

    更新日期:2013-11-01 00:00:00

  • A semi-implantable multichannel telemetry system for continuous electrical, mechanical and hemodynamical recordings in animal cardiac research.

    abstract::We have developed an eight-channel telemetry system for studying experimental models of chronic cardiovascular disease. The system is an extension of a previous device that has been miniaturized, reduced in power consumption and provided with increased functionality. We added sensors for ventricular dimension, and cor...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Kong W,Huang J,Rollins DL,Ideker RE,Smith WM

    更新日期:2007-03-01 00:00:00

  • Relationship between detrended fluctuation analysis and spectral analysis of heart-rate variability.

    abstract::The recently-introduced technique of detrended fluctuation analysis (DFA) for heart-rate variability appears to yield improved prognostic power in cardiovascular disease through calculation of the fractal scaling exponent alpha. However, the physiological meaning of alpha remains unclear. In DFA, the signal is segment...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Willson K,Francis DP,Wensel R,Coats AJ,Parker KH

    更新日期:2002-05-01 00:00:00

  • Automatic sleep-stage scoring based on photoplethysmographic signals.

    abstract:OBJECTIVE:Sleep-stage scoring is important for sleep-quality evaluation and the diagnosis of related diseases. In this study, an automatic sleep-stage scoring method using photoplethysmographic (PPG) signals was proposed. APPROACH:To construct the classification model, we extracted 14 time-domain features, 17 frequenc...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Wu X,Yang J,Pan Y,Zhang X,Luo Y

    更新日期:2020-06-30 00:00:00

  • Determination of Cole parameters in multiple frequency bioelectrical impedance analysis using only the measurement of impedances.

    abstract::Conventional bioimpedance spectrometers measure resistance and reactance over a range of frequencies and, by application of a mathematical model for an equivalent circuit (the Cole model), estimate resistance at zero and infinite frequencies. Fitting of the experimental data to the model is accomplished by iterative, ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Ward LC,Essex T,Cornish BH

    更新日期:2006-09-01 00:00:00

  • Neuromagnetic field strength outside the human head due to impedance changes from neuronal depolarization.

    abstract::The holy grail of neuroimaging would be to have an imaging system, which could image neuronal electrical activity over milliseconds. One way to do this would be by imaging the impedance changes associated with ion channels opening in neuronal membranes in the brain during activity. In principle, we could measure this ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Ahadzi GM,Liston AD,Bayford RH,Holder DS

    更新日期:2004-02-01 00:00:00

  • Multi-frequency parameter mapping of electrical impedance scanning using two kinds of circuit model.

    abstract::Electrical impedance scanning (EIS) is a kind of potential bio-impedance measurement technology, especially aiding the diagnosis of breast cancer in women. By changing the frequency of the driving signal in turn while keeping the other conditions stable, multi-frequency measurement results on the object can be obtaine...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Liu R,Dong X,Fu F,You F,Shi X,Ji Z,Wang K

    更新日期:2007-07-01 00:00:00

  • A multi-frequency EIT system design based on telecommunication signal processors.

    abstract::A multi-frequency electrical impedance tomography system for cardiopulmonary monitoring has been designed with specialized digital signal processors developed primarily for the telecommunications sector. The system consists of two modules: a scan-head and a base-station. The scan-head, located close to the patient's t...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Robitaille N,Guardo R,Maurice I,Hartinger AE,Gagnon H

    更新日期:2009-06-01 00:00:00

  • Reproducibility of regional lung ventilation distribution determined by electrical impedance tomography during mechanical ventilation.

    abstract::Electrical impedance tomography (EIT) has the potential to become a new tool for bedside monitoring of regional lung ventilation. The aim of our study was to assess the reproducibility of regional lung ventilation distribution determined by EIT during mechanical ventilation under identical ventilator settings. The exp...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Frerichs I,Schmitz G,Pulletz S,Schädler D,Zick G,Scholz J,Weiler N

    更新日期:2007-07-01 00:00:00

  • An instrumented timed up and go: the added value of an accelerometer for identifying fall risk in idiopathic fallers.

    abstract::The Timed Up and Go (TUG) test is a widely used measure of mobility and fall risk among older adults that is typically scored using a stopwatch. We tested the hypothesis that a body-fixed accelerometer can enhance the ability of the TUG to identify community-living older adults with a relatively high fall risk of unkn...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Weiss A,Herman T,Plotnik M,Brozgol M,Giladi N,Hausdorff JM

    更新日期:2011-12-01 00:00:00